Abstract: Objective To investigate the proportion of regulatory T lymphocyte (Tregs), T helper cells type 1(Th1) and Th17 subsets in non-surgical hypoparathyroidism (ns-HP). Methods A total of 20 patients with ns-HP , 20 patients with Hashimoto's thyroiditis were included, all patients were followed up during July 2018 to March 2019 at Peking Union Medical College Hospital (PUMCH). Twenty healthy participants were included as control group. The three groups were matched according to gender and age. Flow cytometry were used to test the proportion of Tregs, Th1 and Th17. Multiple linear regression model was used to investigate the predictors of percentage of abnormal T lymphocyte subsets. Results The proportion of Tregs in ns-HP group and Hashimoto's thyroiditis group were lower than that in healthy controls (p＜0.05 and p＜0.01, respectively), but no difference of Tregs proportion between ns-HP group and Hashimoto's thyroiditis group were found. The proportion of Th17 were higher in nsHP and Hashimoto's thyroiditis group than that in healthy controls（p＜0.05 and p＜0.01）No linear correlation was found between the proportion of Tregs, Th17 and other factors. Conclusions The pathology of ns-HP may be associated with changes of lymphocytes subsets distribution.

Key words: hypoparathyroidism, T lymphocyte subsets, regulatory T lymphocyte, T helper cells